The investigation of Capt. Daniel Cruz is the first significant action against a high-ranking official since public scrutiny of the L.A. County jails intensified.

Los Angeles County sheriff's officials have launched an investigation into the performance of a captain who until recently supervised the troubled Men's Central Jail, a source confirmed Wednesday.

The probe into Capt. Daniel Cruz represents the first significant action against a high-ranking sheriff's official since public scrutiny of the department's jails intensified in recent weeks.

In an interview Wednesday, Sheriff Lee Baca declined to detail why Cruz was put on leave. "I'm looking into a few matters," Baca said. "In order to do that, I felt it would be best that he be relieved of duty in the interim."

The source with knowledge of the case said the probe was connected to Cruz's tenure at Men's Central Jail, and would be wide-ranging. The source requested anonymity because he was not authorized to speak to the media about the matter

Cruz, who left Men's Central Jail for Transit Services late last year, has been relieved of duty pending the internal administrative investigation. In these types of probes, department employees can be reinstated without punishment, suspended, demoted or even fired.

Cruz, who could not be reached for an interview, oversaw the Men's Central Jail from April 2008 to December 2010. The Times has reported that sheriff's brass raised warnings in internal audits during that period about inexperienced jailers and excessive force at the downtown L.A. lockup.

The move comes just days after Baca sent a memo to employees warning them not to ignore problems or insulate their bosses from bad news.

"I accepted responsibility for alleged deficiencies in the jails, where it was later revealed that input from a variety of sources, including Department members, was not adequately addressed or possibly ignored. This is unfortunate and unacceptable," Baca wrote.

The county's jails have come under intensifying criticism since The Times reported in September that federal authorities were investigating reports of inmate abuse and other deputy misconduct.

The U.S. attorney's office has demanded a large volume of documents on deputies and others working in the jails, including reports of force used on inmates, since 2009. The county Board of Supervisors has called for reforms and is setting up a commission to investigate the scope of the jails' problems.

Confidential documents reviewed by The Times show that sheriff's officials identified excessive force as a problem in the Men's Central Jail in 2009, when Cruz was running it. The records concluded that some deputies used unnecessary force, then escaped punishment because of shoddy investigations by supervisors.

One of the reports audited more than 100 violent encounters with inmates and found that deputies crafted narratives "dramatized to justify" force. Authorities concluded that some confrontations were triggered by deputies who thought inmates had acted disrespectfully to them — showing "contempt of cop."

Another document showed that the department had placed some of its least experienced deputies to guard its most dangerous inmates on the third floor of the Men's Central Jail, a practice that the memo linked to more frequent clashes on the floor than any other part of the jail.

It is unclear from the documents whether Cruz was provided with their findings or what action he took in response.

Among the most embarrassing events of Cruz's tenure at Men's Central Jail was a fight between some of his deputies at a department Christmas party days before he shifted assignments. Cruz was at the party, which was held at a Montebello banquet hall, when a group of third-floor deputies clashed with others from a different floor.

After the brawl, sheriff's officials said some of the deputies had formed an aggressive clique whose members flashed gang-like three-finger hand signs. The department has moved to fire six deputies in what was described as the largest termination from one incident in recent memory.